ABSTRACT Our recent research discovered that almost 25% of a population-based sample of young transwomen in Brazil tested positive for HIV. This finding is consistent with research demonstrating that transwomen are the population most severely affected by HIV worldwide and face important barriers to accessing effective prevention and care programs. There is no HIV prevention intervention for young transwomen with evidence of efficacy outside the US. We propose a two-phase combination prevention intervention to address the main barriers to HIV prevention and care found in our research in this resource constrained setting. Stigma prevents young transwomen from accessing HIV prevention and care services, despite the fact that such services are freely available to all Brazilians in the public health system care system (i.e., SUS). Young people's HIV testing levels and care access is uneven. Data from our study show that almost no young transwomen regularly got tested for HIV, and given low testing levels, it is unlikely youth are accessing HIV care. In response to NICHD RFA-HD-18-032, we propose the Brilho e Transcender (BeT, or Shine and Transcend) intervention for young transwomen ages 18-24 years old in Brazil. Our proposed intervention uses expertise gleaned from a US based cohort study of young transwomen and knowledge from our cross-sectional transwomen HIV risk study in Brazil. Our study is comprised of two phases to address stigma in the public health system, intervene to overcome youth challenges with health care systems navigation and to scale the intervention widely if proven efficacious. During the 2-year UG3 phase, we propose to develop, implement and measure a highly visible, community-informed social marketing campaign to reduce anti-trans stigma in four SUS clinics currently implementing national PrEP access efforts that are also part of ImPrEP, which is a 3-country PrEP implementation project focused on transgender individuals and MSM. During the UG3 phase, we will also collect formative data to adapt our ARTAS-based system navigation intervention to the cultural context and HIV prevention and care needs of young transwomen in Brazil. After adaptation, we will conduct a small pilot intervention with 20 youth participants to determine preliminary efficacy and demonstrate our ability to recruit youth in this population. Preliminary data gathered from the RCT in the UG3 phase will be used to refine the intervention and justify movement to the UH3 phase and larger RCT to test efficacy of the intervention. During the UH3 phase, we will conduct a RCT with 150 young transwomen randomized to the BeT intervention or control. The intervention will be a digital systems navigation intervention utilizing peers to address youth-specific barriers to HIV prevention and care- namely, risk perception, system navigation skills and health literacy. The intervention will be intensively implemented over three months with follow-up to twelve months. The control arm will receive unidirectional educational text messages for the same period. We will test whether intervention arm participants have an increase in HIV testing frequency, PrEP uptake and HIV care linkage compared to participants in the control arm. A key innovation of our intervention is that it will be delivered digitally by trained transwomen peers. Interventions that require participants to interact on a particular schedule and in-person present a number of problems for young transwomen who face substantial competing needs and barriers to participation. Our intervention is private, can occur on a schedule convenient to participants, and does not require in-person interaction. The latter advantage is particularly salient for young transwomen who risk threats and abuse in public, especially on transportation. The system-navigation intervention promises multiple advantages over existing interventions that require in-person attendance, including more frequent engagement and lower cost of a digital intervention, alignment with the ways young transwomen socialize and interact, and in addressing safety challenges trans people face with participation in placed-based interventions. With proof of efficacy, the intervention can be rapidly brought to scale as a replicable, sustainable, evidence-based intervention for young transwomen in collaboration with the ImPrEP study and the Brazilian Ministry of Health efforts to increase prevention and care access for transwomen, including youth.